[Risk and prognostic analysis of cervical lymph node metastasis in cN+ laryngeal squamous cell carcinoma]

Objective:To analyze the clinical, pathological features and metastatic regularity of cervical lymph node metastasis in cN+ laryngeal squamous cell carcinoma, and to explore its diagnosis and management. Methods:Among 1030 patients with laryngeal squamous cell carcinoma who underwent surgery in the Department of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University from March 2011 to January 2021, 83 patients with cN+ were included in the retrospective analysis of clinical data and follow-up data. Results:Among the 83 cases of cN+ laryngeal carcinoma, there were pN+65 cases and pN-18 cases. The false positive rate of cN+ was 21.7%. cN+ cervical lymph node metastasis was related to classification and staging, and the difference was statistically significant（P<0.05）.The false positive rate of cN+ in different types of laryngeal carcinoma was 57.7% （16/27） in glottic type and 3.9% （2/55） in supraglottic type. With the increase of T stage, the false positive rate decreased.The false positive rates of different CT imaging features were as follows:①Size:the critical lymph nodes of more than 2 sizes were 27.3% （3/11）, the 1~3 cm of lymph nodes was 29.4% （15/51）, and the lymph nodes > 3 cm were not false positive （0/21）;②The enhancement types of uniform enhancement, non-uniform enhancement and circular enhancement were 34.3% （12/35）, 31.6% （6/19） and 0% （0/29） respectively. ③The proportion of unclear shape and boundary of lymph nodes was 0（0/24）.The neck recurrence rate was 2.4% in the selective neck dissection （SND） and 20.0% in the non-SND. The 3-year neck area control rates of SND and non-SND group were 93.7% and 81.1% respectively, and the difference was statistically significant （P < 0.05）. The 3-year cumulative survival rates of pN+ group and pN- group were 75.5% and 87.5%, respectively, and there was no significant difference between the two groups （P > 0.05）. The 3-year cumulative survival rates of lymph node extranodal extension ENE+ group and ENE- group were 50.6% and 79.3%, respectively, and the difference was statistically significant （P < 0.05）. Conclusion: There is false positive in cN+ laryngeal carcinoma, which is related to tumor classification and staging. Preoperative imaging diagnosis of cN+ should not be over-dependent on size, but should be combined with the specific manifestations of lymph node metastasis such as circular enhancement and unclear boundaries. Proper use of SND in the treatment of cN+ laryngeal carcinoma is safe and effective, and reduces the risk of overtreatment. In patients with pN+ laryngeal carcinoma, postoperative supplementary treatment can improve the neck control rate and survival rate. However, even if postoperative treatment is performed in patients with ENE+, it is still an unfavorable factor affecting the prognosis.